package com.github.walterfan.util;

/*
 * Copyright 2002-2009 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import com.github.walterfan.util.CollectionUtils;
import com.github.walterfan.util.ObjectUtils;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.Properties;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;

/**
 * Miscellaneous {@link String} utility methods.
 *
 * <p>Mainly for internal use within the framework; consider
 * <a href="http://jakarta.apache.org/commons/lang/">Jakarta's Commons Lang</a>
 * for a more comprehensive suite of String utilities.
 *
 * <p>This class delivers some simple functionality that should really
 * be provided by the core Java <code>String</code> and {@link StringBuilder}
 * classes, such as the ability to {@link #replace} all occurrences of a given
 * substring in a target string. It also provides easy-to-use methods to convert
 * between delimited strings, such as CSV strings, and collections and arrays.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Keith Donald
 * @author Rob Harrop
 * @author Rick Evans
 * @author Arjen Poutsma
 * @since 16 April 2001
 * @see org.apache.commons.lang.StringUtils
 */
public abstract class StringUtil {

        private static final String FOLDER_SEPARATOR = "/";

        private static final String WINDOWS_FOLDER_SEPARATOR = "\\";

        private static final String TOP_PATH = "..";

        private static final String CURRENT_PATH = ".";

        private static final char EXTENSION_SEPARATOR = '.';


        //---------------------------------------------------------------------
        // General convenience methods for working with Strings
        //---------------------------------------------------------------------

        /**
         * Check that the given CharSequence is neither <code>null</code> nor of length 0.
         * Note: Will return <code>true</code> for a CharSequence that purely consists of whitespace.
         * <p><pre>
         * StringUtils.hasLength(null) = false
         * StringUtils.hasLength("") = false
         * StringUtils.hasLength(" ") = true
         * StringUtils.hasLength("Hello") = true
         * </pre>
         * @param str the CharSequence to check (may be <code>null</code>)
         * @return <code>true</code> if the CharSequence is not null and has length
         * @see #hasText(String)
         */
        public static boolean hasLength(CharSequence str) {
                return (str != null && str.length() > 0);
        }

        /**
         * Check that the given String is neither <code>null</code> nor of length 0.
         * Note: Will return <code>true</code> for a String that purely consists of whitespace.
         * @param str the String to check (may be <code>null</code>)
         * @return <code>true</code> if the String is not null and has length
         * @see #hasLength(CharSequence)
         */
        public static boolean hasLength(String str) {
                return hasLength((CharSequence) str);
        }

        /**
         * Check whether the given CharSequence has actual text.
         * More specifically, returns <code>true</code> if the string not <code>null</code>,
         * its length is greater than 0, and it contains at least one non-whitespace character.
         * <p><pre>
         * StringUtils.hasText(null) = false
         * StringUtils.hasText("") = false
         * StringUtils.hasText(" ") = false
         * StringUtils.hasText("12345") = true
         * StringUtils.hasText(" 12345 ") = true
         * </pre>
         * @param str the CharSequence to check (may be <code>null</code>)
         * @return <code>true</code> if the CharSequence is not <code>null</code>,
         * its length is greater than 0, and it does not contain whitespace only
         * @see java.lang.Character#isWhitespace
         */
        public static boolean hasText(CharSequence str) {
                if (!hasLength(str)) {
                        return false;
                }
                int strLen = str.length();
                for (int i = 0; i < strLen; i++) {
                        if (!Character.isWhitespace(str.charAt(i))) {
                                return true;
                        }
                }
                return false;
        }

        /**
         * Check whether the given String has actual text.
         * More specifically, returns <code>true</code> if the string not <code>null</code>,
         * its length is greater than 0, and it contains at least one non-whitespace character.
         * @param str the String to check (may be <code>null</code>)
         * @return <code>true</code> if the String is not <code>null</code>, its length is
         * greater than 0, and it does not contain whitespace only
         * @see #hasText(CharSequence)
         */
        public static boolean hasText(String str) {
                return hasText((CharSequence) str);
        }

        /**
         * Check whether the given CharSequence contains any whitespace characters.
         * @param str the CharSequence to check (may be <code>null</code>)
         * @return <code>true</code> if the CharSequence is not empty and
         * contains at least 1 whitespace character
         * @see java.lang.Character#isWhitespace
         */
        public static boolean containsWhitespace(CharSequence str) {
                if (!hasLength(str)) {
                        return false;
                }
                int strLen = str.length();
                for (int i = 0; i < strLen; i++) {
                        if (Character.isWhitespace(str.charAt(i))) {
                                return true;
                        }
                }
                return false;
        }

        /**
         * Check whether the given String contains any whitespace characters.
         * @param str the String to check (may be <code>null</code>)
         * @return <code>true</code> if the String is not empty and
         * contains at least 1 whitespace character
         * @see #containsWhitespace(CharSequence)
         */
        public static boolean containsWhitespace(String str) {
                return containsWhitespace((CharSequence) str);
        }

        /**
         * Trim leading and trailing whitespace from the given String.
         * @param str the String to check
         * @return the trimmed String
         * @see java.lang.Character#isWhitespace
         */
        public static String trimWhitespace(String str) {
                if (!hasLength(str)) {
                        return str;
                }
                StringBuilder sb = new StringBuilder(str);
                while (sb.length() > 0 && Character.isWhitespace(sb.charAt(0))) {
                        sb.deleteCharAt(0);
                }
                while (sb.length() > 0 && Character.isWhitespace(sb.charAt(sb.length() - 1))) {
                        sb.deleteCharAt(sb.length() - 1);
                }
                return sb.toString();
        }

        /**
         * Trim <i>all</i> whitespace from the given String:
         * leading, trailing, and inbetween characters.
         * @param str the String to check
         * @return the trimmed String
         * @see java.lang.Character#isWhitespace
         */
        public static String trimAllWhitespace(String str) {
                if (!hasLength(str)) {
                        return str;
                }
                StringBuilder sb = new StringBuilder(str);
                int index = 0;
                while (sb.length() > index) {
                        if (Character.isWhitespace(sb.charAt(index))) {
                                sb.deleteCharAt(index);
                        }
                        else {
                                index++;
                        }
                }
                return sb.toString();
        }

        /**
         * Trim leading whitespace from the given String.
         * @param str the String to check
         * @return the trimmed String
         * @see java.lang.Character#isWhitespace
         */
        public static String trimLeadingWhitespace(String str) {
                if (!hasLength(str)) {
                        return str;
                }
                StringBuilder sb = new StringBuilder(str);
                while (sb.length() > 0 && Character.isWhitespace(sb.charAt(0))) {
                        sb.deleteCharAt(0);
                }
                return sb.toString();
        }

        /**
         * Trim trailing whitespace from the given String.
         * @param str the String to check
         * @return the trimmed String
         * @see java.lang.Character#isWhitespace
         */
        public static String trimTrailingWhitespace(String str) {
                if (!hasLength(str)) {
                        return str;
                }
                StringBuilder sb = new StringBuilder(str);
                while (sb.length() > 0 && Character.isWhitespace(sb.charAt(sb.length() - 1))) {
                        sb.deleteCharAt(sb.length() - 1);
                }
                return sb.toString();
        }

        /**
         * Trim all occurences of the supplied leading character from the given String.
         * @param str the String to check
         * @param leadingCharacter the leading character to be trimmed
         * @return the trimmed String
         */
        public static String trimLeadingCharacter(String str, char leadingCharacter) {
                if (!hasLength(str)) {
                        return str;
                }
                StringBuilder sb = new StringBuilder(str);
                while (sb.length() > 0 && sb.charAt(0) == leadingCharacter) {
                        sb.deleteCharAt(0);
                }
                return sb.toString();
        }

        /**
         * Trim all occurences of the supplied trailing character from the given String.
         * @param str the String to check
         * @param trailingCharacter the trailing character to be trimmed
         * @return the trimmed String
         */
        public static String trimTrailingCharacter(String str, char trailingCharacter) {
                if (!hasLength(str)) {
                        return str;
                }
                StringBuilder sb = new StringBuilder(str);
                while (sb.length() > 0 && sb.charAt(sb.length() - 1) == trailingCharacter) {
                        sb.deleteCharAt(sb.length() - 1);
                }
                return sb.toString();
        }


        /**
         * Test if the given String starts with the specified prefix,
         * ignoring upper/lower case.
         * @param str the String to check
         * @param prefix the prefix to look for
         * @see java.lang.String#startsWith
         */
        public static boolean startsWithIgnoreCase(String str, String prefix) {
                if (str == null || prefix == null) {
                        return false;
                }
                if (str.startsWith(prefix)) {
                        return true;
                }
                if (str.length() < prefix.length()) {
                        return false;
                }
                String lcStr = str.substring(0, prefix.length()).toLowerCase();
                String lcPrefix = prefix.toLowerCase();
                return lcStr.equals(lcPrefix);
        }

        /**
         * Test if the given String ends with the specified suffix,
         * ignoring upper/lower case.
         * @param str the String to check
         * @param suffix the suffix to look for
         * @see java.lang.String#endsWith
         */
        public static boolean endsWithIgnoreCase(String str, String suffix) {
                if (str == null || suffix == null) {
                        return false;
                }
                if (str.endsWith(suffix)) {
                        return true;
                }
                if (str.length() < suffix.length()) {
                        return false;
                }

                String lcStr = str.substring(str.length() - suffix.length()).toLowerCase();
                String lcSuffix = suffix.toLowerCase();
                return lcStr.equals(lcSuffix);
        }

        /**
         * Test whether the given string matches the given substring
         * at the given index.
         * @param str the original string (or StringBuilder)
         * @param index the index in the original string to start matching against
         * @param substring the substring to match at the given index
         */
        public static boolean substringMatch(CharSequence str, int index, CharSequence substring) {
                for (int j = 0; j < substring.length(); j++) {
                        int i = index + j;
                        if (i >= str.length() || str.charAt(i) != substring.charAt(j)) {
                                return false;
                        }
                }
                return true;
        }

        /**
         * Count the occurrences of the substring in string s.
         * @param str string to search in. Return 0 if this is null.
         * @param sub string to search for. Return 0 if this is null.
         */
        public static int countOccurrencesOf(String str, String sub) {
                if (str == null || sub == null || str.length() == 0 || sub.length() == 0) {
                        return 0;
                }
                int count = 0;
                int pos = 0;
                int idx = 0;
                while ((idx = str.indexOf(sub, pos)) != -1) {
                        ++count;
                        pos = idx + sub.length();
                }
                return count;
        }

        /**
         * Replace all occurences of a substring within a string with
         * another string.
         * @param inString String to examine
         * @param oldPattern String to replace
         * @param newPattern String to insert
         * @return a String with the replacements
         */
        public static String replace(String inString, String oldPattern, String newPattern) {
                if (!hasLength(inString) || !hasLength(oldPattern) || newPattern == null) {
                        return inString;
                }
                StringBuilder sb = new StringBuilder();
                int pos = 0; // our position in the old string
                int index = inString.indexOf(oldPattern);
                // the index of an occurrence we've found, or -1
                int patLen = oldPattern.length();
                while (index >= 0) {
                        sb.append(inString.substring(pos, index));
                        sb.append(newPattern);
                        pos = index + patLen;
                        index = inString.indexOf(oldPattern, pos);
                }
                sb.append(inString.substring(pos));
                // remember to append any characters to the right of a match
                return sb.toString();
        }

        /**
         * Delete all occurrences of the given substring.
         * @param inString the original String
         * @param pattern the pattern to delete all occurrences of
         * @return the resulting String
         */
        public static String delete(String inString, String pattern) {
                return replace(inString, pattern, "");
        }

        /**
         * Delete any character in a given String.
         * @param inString the original String
         * @param charsToDelete a set of characters to delete.
         * E.g. "az\n" will delete 'a's, 'z's and new lines.
         * @return the resulting String
         */
        public static String deleteAny(String inString, String charsToDelete) {
                if (!hasLength(inString) || !hasLength(charsToDelete)) {
                        return inString;
                }
                StringBuilder sb = new StringBuilder();
                for (int i = 0; i < inString.length(); i++) {
                        char c = inString.charAt(i);
                        if (charsToDelete.indexOf(c) == -1) {
                                sb.append(c);
                        }
                }
                return sb.toString();
        }


        //---------------------------------------------------------------------
        // Convenience methods for working with formatted Strings
        //---------------------------------------------------------------------

        /**
         * Quote the given String with single quotes.
         * @param str the input String (e.g. "myString")
         * @return the quoted String (e.g. "'myString'"),
         * or <code>null<code> if the input was <code>null</code>
         */
        public static String quote(String str) {
                return (str != null ? "'" + str + "'" : null);
        }

        /**
         * Turn the given Object into a String with single quotes
         * if it is a String; keeping the Object as-is else.
         * @param obj the input Object (e.g. "myString")
         * @return the quoted String (e.g. "'myString'"),
         * or the input object as-is if not a String
         */
        public static Object quoteIfString(Object obj) {
                return (obj instanceof String ? quote((String) obj) : obj);
        }

        /**
         * Unqualify a string qualified by a '.' dot character. For example,
         * "this.name.is.qualified", returns "qualified".
         * @param qualifiedName the qualified name
         */
        public static String unqualify(String qualifiedName) {
                return unqualify(qualifiedName, '.');
        }

        /**
         * Unqualify a string qualified by a separator character. For example,
         * "this:name:is:qualified" returns "qualified" if using a ':' separator.
         * @param qualifiedName the qualified name
         * @param separator the separator
         */
        public static String unqualify(String qualifiedName, char separator) {
                return qualifiedName.substring(qualifiedName.lastIndexOf(separator) + 1);
        }

        /**
         * Capitalize a <code>String</code>, changing the first letter to
         * upper case as per {@link Character#toUpperCase(char)}.
         * No other letters are changed.
         * @param str the String to capitalize, may be <code>null</code>
         * @return the capitalized String, <code>null</code> if null
         */
        public static String capitalize(String str) {
                return changeFirstCharacterCase(str, true);
        }

        /**
         * Uncapitalize a <code>String</code>, changing the first letter to
         * lower case as per {@link Character#toLowerCase(char)}.
         * No other letters are changed.
         * @param str the String to uncapitalize, may be <code>null</code>
         * @return the uncapitalized String, <code>null</code> if null
         */
        public static String uncapitalize(String str) {
                return changeFirstCharacterCase(str, false);
        }

        private static String changeFirstCharacterCase(String str, boolean capitalize) {
                if (str == null || str.length() == 0) {
                        return str;
                }
                StringBuilder sb = new StringBuilder(str.length());
                if (capitalize) {
                        sb.append(Character.toUpperCase(str.charAt(0)));
                }
                else {
                        sb.append(Character.toLowerCase(str.charAt(0)));
                }
                sb.append(str.substring(1));
                return sb.toString();
        }

        /**
         * Extract the filename from the given path,
         * e.g. "mypath/myfile.txt" -> "myfile.txt".
         * @param path the file path (may be <code>null</code>)
         * @return the extracted filename, or <code>null</code> if none
         */
        public static String getFilename(String path) {
                if (path == null) {
                        return null;
                }
                int separatorIndex = path.lastIndexOf(FOLDER_SEPARATOR);
                return (separatorIndex != -1 ? path.substring(separatorIndex + 1) : path);
        }

        /**
         * Extract the filename extension from the given path,
         * e.g. "mypath/myfile.txt" -> "txt".
         * @param path the file path (may be <code>null</code>)
         * @return the extracted filename extension, or <code>null</code> if none
         */
        public static String getFilenameExtension(String path) {
                if (path == null) {
                        return null;
                }
                int sepIndex = path.lastIndexOf(EXTENSION_SEPARATOR);
                return (sepIndex != -1 ? path.substring(sepIndex + 1) : null);
        }

        /**
         * Strip the filename extension from the given path,
         * e.g. "mypath/myfile.txt" -> "mypath/myfile".
         * @param path the file path (may be <code>null</code>)
         * @return the path with stripped filename extension,
         * or <code>null</code> if none
         */
        public static String stripFilenameExtension(String path) {
                if (path == null) {
                        return null;
                }
                int sepIndex = path.lastIndexOf(EXTENSION_SEPARATOR);
                return (sepIndex != -1 ? path.substring(0, sepIndex) : path);
        }

        /**
         * Apply the given relative path to the given path,
         * assuming standard Java folder separation (i.e. "/" separators);
         * @param path the path to start from (usually a full file path)
         * @param relativePath the relative path to apply
         * (relative to the full file path above)
         * @return the full file path that results from applying the relative path
         */
        public static String applyRelativePath(String path, String relativePath) {
                int separatorIndex = path.lastIndexOf(FOLDER_SEPARATOR);
                if (separatorIndex != -1) {
                        String newPath = path.substring(0, separatorIndex);
                        if (!relativePath.startsWith(FOLDER_SEPARATOR)) {
                                newPath += FOLDER_SEPARATOR;
                        }
                        return newPath + relativePath;
                }
                else {
                        return relativePath;
                }
        }

        /**
         * Normalize the path by suppressing sequences like "path/.." and
         * inner simple dots.
         * <p>The result is convenient for path comparison. For other uses,
         * notice that Windows separators ("\") are replaced by simple slashes.
         * @param path the original path
         * @return the normalized path
         */
        public static String cleanPath(String path) {
                if (path == null) {
                        return null;
                }
                String pathToUse = replace(path, WINDOWS_FOLDER_SEPARATOR, FOLDER_SEPARATOR);

                // Strip prefix from path to analyze, to not treat it as part of the
                // first path element. This is necessary to correctly parse paths like
                // "file:core/../core/io/Resource.class", where the ".." should just
                // strip the first "core" directory while keeping the "file:" prefix.
                int prefixIndex = pathToUse.indexOf(":");
                String prefix = "";
                if (prefixIndex != -1) {
                        prefix = pathToUse.substring(0, prefixIndex + 1);
                        pathToUse = pathToUse.substring(prefixIndex + 1);
                }
                if (pathToUse.startsWith(FOLDER_SEPARATOR)) {
                        prefix = prefix + FOLDER_SEPARATOR;
                        pathToUse = pathToUse.substring(1);
                }

                String[] pathArray = delimitedListToStringArray(pathToUse, FOLDER_SEPARATOR);
                List<String> pathElements = new LinkedList<String>();
                int tops = 0;

                for (int i = pathArray.length - 1; i >= 0; i--) {
                        String element = pathArray[i];
                        if (CURRENT_PATH.equals(element)) {
                                // Points to current directory - drop it.
                        }
                        else if (TOP_PATH.equals(element)) {
                                // Registering top path found.
                                tops++;
                        }
                        else {
                                if (tops > 0) {
                                        // Merging path element with element corresponding to top path.
                                        tops--;
                                }
                                else {
                                        // Normal path element found.
                                        pathElements.add(0, element);
                                }
                        }
                }

                // Remaining top paths need to be retained.
                for (int i = 0; i < tops; i++) {
                        pathElements.add(0, TOP_PATH);
                }

                return prefix + collectionToDelimitedString(pathElements, FOLDER_SEPARATOR);
        }

        /**
         * Compare two paths after normalization of them.
         * @param path1 first path for comparison
         * @param path2 second path for comparison
         * @return whether the two paths are equivalent after normalization
         */
        public static boolean pathEquals(String path1, String path2) {
                return cleanPath(path1).equals(cleanPath(path2));
        }

        /**
         * Parse the given <code>localeString</code> into a {@link Locale}.
         * <p>This is the inverse operation of {@link Locale#toString Locale's toString}.
         * @param localeString the locale string, following <code>Locale's</code>
         * <code>toString()</code> format ("en", "en_UK", etc);
         * also accepts spaces as separators, as an alternative to underscores
         * @return a corresponding <code>Locale</code> instance
         */
        public static Locale parseLocaleString(String localeString) {
                String[] parts = tokenizeToStringArray(localeString, "_ ", false, false);
                String language = (parts.length > 0 ? parts[0] : "");
                String country = (parts.length > 1 ? parts[1] : "");
                String variant = "";
                if (parts.length >= 2) {
                        // There is definitely a variant, and it is everything after the country
                        // code sans the separator between the country code and the variant.
                        int endIndexOfCountryCode = localeString.indexOf(country) + country.length();
                        // Strip off any leading '_' and whitespace, what's left is the variant.
                        variant = trimLeadingWhitespace(localeString.substring(endIndexOfCountryCode));
                        if (variant.startsWith("_")) {
                                variant = trimLeadingCharacter(variant, '_');
                        }
                }
                return (language.length() > 0 ? new Locale(language, country, variant) : null);
        }

        /**
         * Determine the RFC 3066 compliant language tag,
         * as used for the HTTP "Accept-Language" header.
         * @param locale the Locale to transform to a language tag
         * @return the RFC 3066 compliant language tag as String
         */
        public static String toLanguageTag(Locale locale) {
                return locale.getLanguage() + (hasText(locale.getCountry()) ? "-" + locale.getCountry() : "");
        }


        //---------------------------------------------------------------------
        // Convenience methods for working with String arrays
        //---------------------------------------------------------------------

        /**
         * Append the given String to the given String array, returning a new array
         * consisting of the input array contents plus the given String.
         * @param array the array to append to (can be <code>null</code>)
         * @param str the String to append
         * @return the new array (never <code>null</code>)
         */
        public static String[] addStringToArray(String[] array, String str) {
                if (ObjectUtils.isEmpty(array)) {
                        return new String[] {str};
                }
                String[] newArr = new String[array.length + 1];
                System.arraycopy(array, 0, newArr, 0, array.length);
                newArr[array.length] = str;
                return newArr;
        }

        /**
         * Concatenate the given String arrays into one,
         * with overlapping array elements included twice.
         * <p>The order of elements in the original arrays is preserved.
         * @param array1 the first array (can be <code>null</code>)
         * @param array2 the second array (can be <code>null</code>)
         * @return the new array (<code>null</code> if both given arrays were <code>null</code>)
         */
        public static String[] concatenateStringArrays(String[] array1, String[] array2) {
                if (ObjectUtils.isEmpty(array1)) {
                        return array2;
                }
                if (ObjectUtils.isEmpty(array2)) {
                        return array1;
                }
                String[] newArr = new String[array1.length + array2.length];
                System.arraycopy(array1, 0, newArr, 0, array1.length);
                System.arraycopy(array2, 0, newArr, array1.length, array2.length);
                return newArr;
        }

        /**
         * Merge the given String arrays into one, with overlapping
         * array elements only included once.
         * <p>The order of elements in the original arrays is preserved
         * (with the exception of overlapping elements, which are only
         * included on their first occurence).
         * @param array1 the first array (can be <code>null</code>)
         * @param array2 the second array (can be <code>null</code>)
         * @return the new array (<code>null</code> if both given arrays were <code>null</code>)
         */
        public static String[] mergeStringArrays(String[] array1, String[] array2) {
                if (ObjectUtils.isEmpty(array1)) {
                        return array2;
                }
                if (ObjectUtils.isEmpty(array2)) {
                        return array1;
                }
                List<String> result = new ArrayList<String>();
                result.addAll(Arrays.asList(array1));
                for (String str : array2) {
                        if (!result.contains(str)) {
                                result.add(str);
                        }
                }
                return toStringArray(result);
        }

        public static String nl2br(String text) {
            return text.replaceAll("\n","<BR />");
        }
        /**
         * Turn given source String array into sorted array.
         * @param array the source array
         * @return the sorted array (never <code>null</code>)
         */
        public static String[] sortStringArray(String[] array) {
                if (ObjectUtils.isEmpty(array)) {
                        return new String[0];
                }
                Arrays.sort(array);
                return array;
        }

        /**
         * Copy the given Collection into a String array.
         * The Collection must contain String elements only.
         * @param collection the Collection to copy
         * @return the String array (<code>null</code> if the passed-in
         * Collection was <code>null</code>)
         */
        public static String[] toStringArray(Collection<String> collection) {
                if (collection == null) {
                        return null;
                }
                return collection.toArray(new String[collection.size()]);
        }

        /**
         * Copy the given Enumeration into a String array.
         * The Enumeration must contain String elements only.
         * @param enumeration the Enumeration to copy
         * @return the String array (<code>null</code> if the passed-in
         * Enumeration was <code>null</code>)
         */
        public static String[] toStringArray(Enumeration<String> enumeration) {
                if (enumeration == null) {
                        return null;
                }
                List<String> list = Collections.list(enumeration);
                return list.toArray(new String[list.size()]);
        }

        /**
         * Trim the elements of the given String array,
         * calling <code>String.trim()</code> on each of them.
         * @param array the original String array
         * @return the resulting array (of the same size) with trimmed elements
         */
        public static String[] trimArrayElements(String[] array) {
                if (ObjectUtils.isEmpty(array)) {
                        return new String[0];
                }
                String[] result = new String[array.length];
                for (int i = 0; i < array.length; i++) {
                        String element = array[i];
                        result[i] = (element != null ? element.trim() : null);
                }
                return result;
        }

        /**
         * Remove duplicate Strings from the given array.
         * Also sorts the array, as it uses a TreeSet.
         * @param array the String array
         * @return an array without duplicates, in natural sort order
         */
        public static String[] removeDuplicateStrings(String[] array) {
                if (ObjectUtils.isEmpty(array)) {
                        return array;
                }
                Set<String> set = new TreeSet<String>();
                for (String element : array) {
                        set.add(element);
                }
                return toStringArray(set);
        }

        /**
         * Split a String at the first occurrence of the delimiter.
         * Does not include the delimiter in the result.
         * @param toSplit the string to split
         * @param delimiter to split the string up with
         * @return a two element array with index 0 being before the delimiter, and
         * index 1 being after the delimiter (neither element includes the delimiter);
         * or <code>null</code> if the delimiter wasn't found in the given input String
         */
        public static String[] split(String toSplit, String delimiter) {
                if (!hasLength(toSplit) || !hasLength(delimiter)) {
                        return null;
                }
                int offset = toSplit.indexOf(delimiter);
                if (offset < 0) {
                        return null;
                }
                String beforeDelimiter = toSplit.substring(0, offset);
                String afterDelimiter = toSplit.substring(offset + delimiter.length());
                return new String[] {beforeDelimiter, afterDelimiter};
        }

        /**
         * Take an array Strings and split each element based on the given delimiter.
         * A <code>Properties</code> instance is then generated, with the left of the
         * delimiter providing the key, and the right of the delimiter providing the value.
         * <p>Will trim both the key and value before adding them to the
         * <code>Properties</code> instance.
         * @param array the array to process
         * @param delimiter to split each element using (typically the equals symbol)
         * @return a <code>Properties</code> instance representing the array contents,
         * or <code>null</code> if the array to process was null or empty
         */
        public static Properties splitArrayElementsIntoProperties(String[] array, String delimiter) {
                return splitArrayElementsIntoProperties(array, delimiter, null);
        }

        /**
         * Take an array Strings and split each element based on the given delimiter.
         * A <code>Properties</code> instance is then generated, with the left of the
         * delimiter providing the key, and the right of the delimiter providing the value.
         * <p>Will trim both the key and value before adding them to the
         * <code>Properties</code> instance.
         * @param array the array to process
         * @param delimiter to split each element using (typically the equals symbol)
         * @param charsToDelete one or more characters to remove from each element
         * prior to attempting the split operation (typically the quotation mark
         * symbol), or <code>null</code> if no removal should occur
         * @return a <code>Properties</code> instance representing the array contents,
         * or <code>null</code> if the array to process was <code>null</code> or empty
         */
        public static Properties splitArrayElementsIntoProperties(
                String[] array, String delimiter, String charsToDelete) {

                if (ObjectUtils.isEmpty(array)) {
                        return null;
                }
                Properties result = new Properties();
                for (String element : array) {
                        if (charsToDelete != null) {
                                element = deleteAny(element, charsToDelete);
                        }
                        String[] splittedElement = split(element, delimiter);
                        if (splittedElement == null) {
                                continue;
                        }
                        result.setProperty(splittedElement[0].trim(), splittedElement[1].trim());
                }
                return result;
        }

        /**
         * Tokenize the given String into a String array via a StringTokenizer.
         * Trims tokens and omits empty tokens.
         * <p>The given delimiters string is supposed to consist of any number of
         * delimiter characters. Each of those characters can be used to separate
         * tokens. A delimiter is always a single character; for multi-character
         * delimiters, consider using <code>delimitedListToStringArray</code>
         * @param str the String to tokenize
         * @param delimiters the delimiter characters, assembled as String
         * (each of those characters is individually considered as delimiter).
         * @return an array of the tokens
         * @see java.util.StringTokenizer
         * @see java.lang.String#trim()
         * @see #delimitedListToStringArray
         */
        public static String[] tokenizeToStringArray(String str, String delimiters) {
                return tokenizeToStringArray(str, delimiters, true, true);
        }

        /**
         * Tokenize the given String into a String array via a StringTokenizer.
         * <p>The given delimiters string is supposed to consist of any number of
         * delimiter characters. Each of those characters can be used to separate
         * tokens. A delimiter is always a single character; for multi-character
         * delimiters, consider using <code>delimitedListToStringArray</code>
         * @param str the String to tokenize
         * @param delimiters the delimiter characters, assembled as String
         * (each of those characters is individually considered as delimiter)
         * @param trimTokens trim the tokens via String's <code>trim</code>
         * @param ignoreEmptyTokens omit empty tokens from the result array
         * (only applies to tokens that are empty after trimming; StringTokenizer
         * will not consider subsequent delimiters as token in the first place).
         * @return an array of the tokens (<code>null</code> if the input String
         * was <code>null</code>)
         * @see java.util.StringTokenizer
         * @see java.lang.String#trim()
         * @see #delimitedListToStringArray
         */
        public static String[] tokenizeToStringArray(
                String str, String delimiters, boolean trimTokens, boolean ignoreEmptyTokens) {

                if (str == null) {
                        return null;
                }
                StringTokenizer st = new StringTokenizer(str, delimiters);
                List<String> tokens = new ArrayList<String>();
                while (st.hasMoreTokens()) {
                        String token = st.nextToken();
                        if (trimTokens) {
                                token = token.trim();
                        }
                        if (!ignoreEmptyTokens || token.length() > 0) {
                                tokens.add(token);
                        }
                }
                return toStringArray(tokens);
        }

        /**
         * Take a String which is a delimited list and convert it to a String array.
         * <p>A single delimiter can consists of more than one character: It will still
         * be considered as single delimiter string, rather than as bunch of potential
         * delimiter characters - in contrast to <code>tokenizeToStringArray</code>.
         * @param str the input String
         * @param delimiter the delimiter between elements (this is a single delimiter,
         * rather than a bunch individual delimiter characters)
         * @return an array of the tokens in the list
         * @see #tokenizeToStringArray
         */
        public static String[] delimitedListToStringArray(String str, String delimiter) {
                return delimitedListToStringArray(str, delimiter, null);
        }

        /**
         * Take a String which is a delimited list and convert it to a String array.
         * <p>A single delimiter can consists of more than one character: It will still
         * be considered as single delimiter string, rather than as bunch of potential
         * delimiter characters - in contrast to <code>tokenizeToStringArray</code>.
         * @param str the input String
         * @param delimiter the delimiter between elements (this is a single delimiter,
         * rather than a bunch individual delimiter characters)
         * @param charsToDelete a set of characters to delete. Useful for deleting unwanted
         * line breaks: e.g. "\r\n\f" will delete all new lines and line feeds in a String.
         * @return an array of the tokens in the list
         * @see #tokenizeToStringArray
         */
        public static String[] delimitedListToStringArray(String str, String delimiter, String charsToDelete) {
                if (str == null) {
                        return new String[0];
                }
                if (delimiter == null) {
                        return new String[] {str};
                }
                List<String> result = new ArrayList<String>();
                if ("".equals(delimiter)) {
                        for (int i = 0; i < str.length(); i++) {
                                result.add(deleteAny(str.substring(i, i + 1), charsToDelete));
                        }
                }
                else {
                        int pos = 0;
                        int delPos = 0;
                        while ((delPos = str.indexOf(delimiter, pos)) != -1) {
                                result.add(deleteAny(str.substring(pos, delPos), charsToDelete));
                                pos = delPos + delimiter.length();
                        }
                        if (str.length() > 0 && pos <= str.length()) {
                                // Add rest of String, but not in case of empty input.
                                result.add(deleteAny(str.substring(pos), charsToDelete));
                        }
                }
                return toStringArray(result);
        }

        /**
         * Convert a CSV list into an array of Strings.
         * @param str the input String
         * @return an array of Strings, or the empty array in case of empty input
         */
        public static String[] commaDelimitedListToStringArray(String str) {
                return delimitedListToStringArray(str, ",");
        }

        /**
         * Convenience method to convert a CSV string list to a set.
         * Note that this will suppress duplicates.
         * @param str the input String
         * @return a Set of String entries in the list
         */
        public static Set<String> commaDelimitedListToSet(String str) {
                Set<String> set = new TreeSet<String>();
                String[] tokens = commaDelimitedListToStringArray(str);
                for (String token : tokens) {
                        set.add(token);
                }
                return set;
        }

        /**
         * Convenience method to return a Collection as a delimited (e.g. CSV)
         * String. E.g. useful for <code>toString()</code> implementations.
         * @param coll the Collection to display
         * @param delim the delimiter to use (probably a ",")
         * @param prefix the String to start each element with
         * @param suffix the String to end each element with
         * @return the delimited String
         */
        public static String collectionToDelimitedString(Collection coll, String delim, String prefix, String suffix) {
                if (CollectionUtils.isEmpty(coll)) {
                        return "";
                }
                StringBuilder sb = new StringBuilder();
                Iterator it = coll.iterator();
                while (it.hasNext()) {
                        sb.append(prefix).append(it.next()).append(suffix);
                        if (it.hasNext()) {
                                sb.append(delim);
                        }
                }
                return sb.toString();
        }

        /**
         * Convenience method to return a Collection as a delimited (e.g. CSV)
         * String. E.g. useful for <code>toString()</code> implementations.
         * @param coll the Collection to display
         * @param delim the delimiter to use (probably a ",")
         * @return the delimited String
         */
        public static String collectionToDelimitedString(Collection coll, String delim) {
                return collectionToDelimitedString(coll, delim, "", "");
        }

        /**
         * Convenience method to return a Collection as a CSV String.
         * E.g. useful for <code>toString()</code> implementations.
         * @param coll the Collection to display
         * @return the delimited String
         */
        public static String collectionToCommaDelimitedString(Collection coll) {
                return collectionToDelimitedString(coll, ",");
        }

        /**
         * Convenience method to return a String array as a delimited (e.g. CSV)
         * String. E.g. useful for <code>toString()</code> implementations.
         * @param arr the array to display
         * @param delim the delimiter to use (probably a ",")
         * @return the delimited String
         */
        public static String arrayToDelimitedString(Object[] arr, String delim) {
                if (ObjectUtils.isEmpty(arr)) {
                        return "";
                }
                StringBuilder sb = new StringBuilder();
                for (int i = 0; i < arr.length; i++) {
                        if (i > 0) {
                                sb.append(delim);
                        }
                        sb.append(arr[i]);
                }
                return sb.toString();
        }

        /**
         * Convenience method to return a String array as a CSV String.
         * E.g. useful for <code>toString()</code> implementations.
         * @param arr the array to display
         * @return the delimited String
         */
        public static String arrayToCommaDelimitedString(Object[] arr) {
                return arrayToDelimitedString(arr, ",");
        }


        public static void main(String[] args) throws ParseException {
                SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssXXX");

                String dateString = format.format( new Date()   );
                Date date       = format.parse ( "2019-08-13T21:57:48+08:00" );
                //String pattern = "yyyy-MM-dd'T'HH:mm:ssXXX";
                //ZonedDateTime ret = ZonedDateTime.parse("2019-08-13T21:57:48+08:00");
                System.out.println(dateString + "/" + date.toString());

        }
}
